Method of making a connector tee for pressure pipe lines

ABSTRACT

Metallic connector Tees for pressure pipes of the larger sizes and wall-thicknesses, which cannot be efficiently and economically made from pipe, and which heretofore have been made by relatively expensive block forging methods, are made by heating a solid metal work-piece of round cross section and appropriate size to forging temperature; peripherally confining the heated solid metal workpiece; and hollow-punching it in axially offset relationship with respect thereto in such manner as to provide a selected wall portion which is sufficiently thick as to permit the formation of the branch pipe passages therein while still retaining sufficient metal to compensate by way of reinforcement for the weakening of the wall caused by the formation of said passages, and without reducing the thickness of the opposite portion of the wall of the work-piece below a predetermined point.

United States Patent [191 Moore METHOD OF MAKING A CONNECTOR TEE FORPRESSURE PIPE LINES Charles H. Moore, 645 Matanzas Court, Fort MyersBeach, Fla. 33931 Filed: Sept. 21, 1972 Appl. No.: 291,040

Related U.S. Application Data Continuation-in-part of Ser; No. 142,744,May 12, 1971, which is a continuation-in-part of Ser. No.

Inventor:

- 720,658, April 11, 1968, abandoned.

U.S. Cl.. 29/157 T, 72/364, 72/368,

Int. Cl... B21d 53/00, B2lk 29/00, B23p 15/00 Field of Search 29/157 R,157 T;

References Cited UNITED STATES PATENTS Primary Examiner-Charles W.Lanham Assistant Examiner-E. M. Combs Attorney-Robert U. Geib, Jr.

[57] ABSTRACT Metallic connector Tees for pressure pipes of the largersizes and wall-thicknesses, which cannot be efficiently and economicallymade from pipe, and which heretofore have been made by relativelyexpensive block forging methods, are made by heating a solid metalwork-piece of round cross section and appropriate size to forgingtemperature; peripherally confining the heated solid metal workpiece;and hollow-punching it in axially offset relationship with respectthereto in such manner as to provide a selected wall portion which issufficiently thick as to permit the formation of the branch pipepassages therein while still retaining sufficient metal to compensate byway of reinforcement for the weakening of the wall caused by theformation of said passages, and without reducing the thickness of theopposite portion of the wall of the work-piece below a predeterminedpoint.

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ATTORNEY PATENTEU M25975 SHEUZUFS INVENTOR dfi/mezfsfifjfaa ATTORNEYPMENIED 3.740.813

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ATTORNEY v METHOD OF MAKING A CONNECTOR TEE FOR PRESSURE PIPE LINES Thepresent application is a continuation-in-part of my present applicationSer. No. 142,744, filed May 12, 1971 entitled Method of Making aConnector Tee for Pressure Pipe Lines, which, in turn, is acontinuationin-part of my earlier filed patent application Ser. No.720,658, filed Apr. 11, 1968 entitled Method of Making Connector MembersFor High Pressure Pipes" (now abandoned).

BACKGROUND OF THE INVENTION In the past it has been customary to makemetallic connectors for smaller size pressure pipesfrom pipe or tubing;and in the case of the larger sizes, commencing at approximately 8-inchnominal pipe size with an accompanying wall-thickness of 0.718 inch ormore, which couldnt satisfactorily be made from pipe or tube, to resortto drop forging methods.

Pipe of the sizes which previously have been difficult to form into Teeconnectors and which caused resort to drop forging methods include:

Schedule commencing with 18 inch Nominal Pipe Size (wall-thickness 0.750inch) Schedule (c) commencing with 14 inch Nominal Pipe Size(wall-thickness 0.750 inch) and Schedule commencing with 10 inch NominalPipe Size (wall-thickness 0.718 inch) Schedule commencing with 8 inchNominal Pipe Size (wall-thickness 0.718 inch) Schedule commencing with 8inch Nominal Pipe Size (wall-thickness 0.812 inch) Schedule commencingwith 8-inch Nominal Pipe Size (wall-thickness 0.906'inch) and DoubleExtra Strong commencing with 8-inch Nominal Pipe Size(wall-thickness'O.875 inch).

THE INVENTION In order to circumvent the use of drop forging meth odswhich are expensive to conduct, as well as having other advantages, 1have discovered that metallic Tee connectors, and modified Teeconnectors, for the larger size pipes for pressure pipe lines, i.e.approximately 8-inch nominal pipe size with an accompanyingwall-thickness of 0.718-inch wall-thickness or greater, cansatisfactorily be made by a relatively simple and inexpensive hollowingpunching method provided it is carried out in a certain well-definedmanner, as will appear hereinafter.

It has, of course, long been recognized that any opening made in a mainpipe (or run) for a branch connection interrupts the uniformity of hoopstresses in the wall of the pipe and results in these stresses beingconcentrated and intensified at the edges which define the opening.These hoop stresses are directly proportional to the pressure andhydraulic diameter of the section and inversely proportional to thewall-thickness of the section.

The rules for strengthening such connections or joints are equallywell-known, having been established by various codes such as the A.S.A.code for pressure piping, the A.S.M.E. power boiler code or by suchmanufacturing codes as the A.S.A. Standard B-l6.9.

The A.S.M.E. Boiler Code provides that the area surrounding an openingmust be adequately reinforced; and defines the area of reinforcement orstrengthening of an opening as confined to a rectangle which is limitedin its outside diameter by two 2) times the diameter of the opening.

The other limitation as to the confinement of the area of reinforcementunder the A.S.M.E. Boiler Code is two and one-half (2.5) times thethickness of the shell both above and below the opening.

These rulesfor the strengthening or reinforcement of the areas referredto in Tee connectors and the like are described in a number ofapplicants patents, including US. Pat. No. 3,392,994, dated July 16,1968 and entitled Connector Means For Pressure Pipelines.

According to prior art practices, in the production of a pipe fitting orconnector member by the block forging method and for the larger sizesreferred to, a forging with a square or rectangular cross-section isfirst obtained; then those portions of the square or rectangularcross-section which are not essential to the shape of the desired Tee ormodified Tee are cut-off or burned-off, followed by cutting or boringthe forged block to provide the desired fluid passages. Besides beingquite costly, this series of steps does very little toward the solutionof the problem that square or rectangular billets of metal (whether ofcarbon steel or various alloys) are characterized by unsoundness at thecenter due to piping caused by impurities, occlusions, gas pockets, etc.This inherent unsoundness is, of course, caused by the differentialsolidification or selective freezing action of the cast ingot. Thepipes" in the center of the ingot are only slightly removed after it hasbeen cropped and forged (by rolling, pressing or hammering) into thebillet or work-piece of square or rectangular crosssection. 1

It has been conclusively demonstrated that even the cutting or boringsteps to form the fluid passages in the block forging or billet ofrectangular cross-section, as practicedin the prior art do not entirelyremove the unsound metal caused by the piping during the ingot phase andthis is true even if the ingot is subjected to sufficient plasticdeformation to reduce its thickness by as much as one-fourth orone-third.

Among the objects of the present invention is the provision of arelatively simple and inexpensive method of making very sound fittingsor connector members for large size high pressure pipes, andparticularly those of Tee or modified Tee formation, which avoid thedifficulties and disadvantages referred to.

Another object is to provide one-piece Tee or modified Tee connectormembers for large size pipes carrying fluids under high pressures whichare metallurgically sounder throughout than those which are produced inconformity with prior art practices; and which, in addition, are soshaped that a portion of the metal of which they are composed ispositioned so as to provide increased wall-thickness and strength (i.e.reinforcement) at areas which ordinarily are least resistant to burstingpressures.

Still another object is the provision of one-piece connector members ofthe type described which possess the advantages referred to, and whereinthe forging is sounder and with better grain orientation.

The foregoing and other objects and advantages will be more readilyunderstood after referring to the following description and accompanyingdrawings wherein like reference numerals designate like parts, andwherein:

FIG. 1 is a series of bracketed-schematic elevational views illustratingfour rolling or forging steps which, ac-

cording to the teachings of the present invention, are employed intransforming a billet of rectangular cross section into one of roundcross-section;

FIG. 2 is a series of bracketed schematic elevational views illustratingfurther treatment of the round billet as obtained by the fourth step ofFIG. 1; and more specifically the punching of the round billet in suchmanner as to obtain a longitudinally extending but axially off-setcylindrical bore;

FIG. 3 is an end elevational view illustrating the round billet with itslongitudinally extending, axially off-set cylindrical bore immediatelyprior to the formation therein of the branch pipe passage of a Teefitting which extends right-angularly with respect to, and communicateswith, the longitudinally extending, axially off-set cylindrical borewhich forms the line pipe portion of the Tee;

FIG. 4 is an end elevational view of the completed Tee fitting whichcomprises the two line pipe connections and the single branch pipeconnection;

FIG. 5 is a side elevational view of the showing of FIG. 4;

FIG. 6 is a side elevational view illustrating a modified form of theinvention which comprises a header or common manifold communicating witha series of branch pipes; and

FIG. 7 is an end elevational view of the showing of FIG. 6.

Referring more particularly to the drawings, in FIG. 1 the numerals land 2 designate a pair of cooperating lower and upper forging dies orrolls, respectively, which are adapted to progressively transform thebillet of initially rectangular cross-section into one of roundcross-section, the four phases thereof being indicated on the work-pieceat A, B, C and D.

As stated earlier herein the plastic deformation of the ingot (notshown) to provide the billet A of rectangular cross-section serves toclose up some of the pipes, etc., and therefore eliminate some of theunsound metal which is adjacent the center.

However, the additional plastic deformation which is caused bytransforming the billet or work-piece from rectangular to roundcross-section is even more beneficial in closing up pipes, etc., andthereby further eliminating unsound metal adjacent the center.

Now referring to FIG. 2, after the round cross-section has beenobtained, the work-piece D is placed in a cylindrical die 5 andsubjected to the action of a hollow punch 7 which is located andarranged against a knife block 8 to punch-out a longitudinally extendingoff-set cylindrical bore 10.

As schematically represented in the three stages of FIG. 2, the punch 7is moved downwardly and longitudinally through the round billet D in theaxially off-set relationship shown, the resulting slug or core E beingutilized as scrap in succeeding melting and casting operations or asstock for smaller pipe connectors.

It will, of course, be understood by those skilled in the art that theinstrumentalities of FIG. 1, which trans form the billet fromrectangular to round cross-section, and the instrumentalities of FIG. 2,which accomplish the axially off-set punching operation, may be entirelyconventional in form; and as such form no part of the present invention.

Referring now to FIG. 3, the axially off-set punched out portion 10 ofthe round billet or work-piece D which is provided by the removal of theslug or core E 4 shown in FIG. 2, is of the same, or substantially thesame, diameter as the inside diameter of the line pipes which are tobeconnected thereto.

The thinnest portion of the wall of the axially off-set cylindrical bore10 of the work-piece D is indicated at 12; and the diametricallyopposite, and thickest, portion at 14, the latter providing an idealmass of metal for the reinforcement of that portion thereof whereinthere is formed branch passageway 15 which is to communicate with thebore 10.

This distribution of metal, as described immediately hereinbeforeprovides intermediate walls 16 which, while thinner than the thickestportion 14, are materially thicker than the thinnest portion 12 of thewall.

Considerable care must be taken to insure the positioning of thehollow-punch 7 in such manner that not only will there be adequatereinforcement at the thickest portion 14 to compensate for theweaknesses imparted by the removal of the metal to provide thepassageway 15, but also to prevent excessive reduction in the thinnestportion 12.

In the case of conventional Tee connector members, it is the side areaswhich are most likely to fail under bursting pressures; whereas in Teeconnector members which embody the teachings of the present inventionincreased resistance is provided by the increased wallthickness at allpoints, even at the portion 12 which is itself not less thanthree-fourths inch thicker than the minimum required wall thickness ascalculated by accepted methods.

Immediately following is a specific example of a forging which has beenformed in accordance with the teachings of the invention:

EXAMPLE Dimensions of Off-Center Punched Cylindrical Forging Weight4,120 Pounds Width 26 inches Depth 26 Va inches Length 27 inchesDiameter of Off-Center Cylindrical bore l4.438 inches With the removalfrom the off-center punched cylindrical forging of the mass of metal atX, Y and Z as required to shape-up the Tee connector, the followingdimensions will be obtained:

End-to-end along line pipe passageways 27 inches End of branch-pipepassageway to axis of line pipe passageway 13.5 inches Diameter of linepipe passageway 14.438 inches Diameter of branch pipe passageway 14.438

inches The outer ends of the two line pipe connections and the outer endof the single branch pipe connection are provided with the usualbevelled portions 10a and 150, respectively, as shown in FIGS. 4 and 5.

The Tee connector member made in the manner described, and possessingthe dimensional characteristics set forth herein, is intended forconnecting standard Schedule I pipe which has an outside diameter of 18inches, an inside diameter of 14.438 inches, and accordingly awall-thickness of 1.781 inches. It will be readily understood by thoseskilled in the art that the invention is not limited to a full size Teeas described since it is equally applicable to reducing Tees, etc.

Referring to FIGS. 6 and 7, a modified form of the invention alsocontemplates a header comprising an elongated work-piece of roundcross-section with a longitudinally extending axially off-set bore whichmay be identical with the bore as previously described, and which formsa manifold; together with a series of spaced areas of greater metaldistribution each of which is apertured to provide a branch passageextending at right-angles to, and communicating with, the elongatedoff-set bore.

While I have shown and described certain specific embodiments of thepresent invention, it will be readily understood by those skilled in theart that I do not wish to be limited exactly thereto, since variousmodifications may be made without departing from the scope of theinvention as defined in the appended claims.

I claim:

1. The method of making a metallic connector Tee for connecting pressurepipes of approximately 8-inch Nominal Pipe Size and a wall-thickness ofat least 0.718 inch. which consists essentially of a. heating a solidmetal work-piece of round crosssection and appropriate size to forgingtemperature;

b. peripherally confining the so-heated solid metal work-piecethroughout substantially its entire length;

c. positioning a single, round, hollow punch longitudinally of saidwork-piece but in axially off-set relationship with respect theretowhile said work-piece is heated and peripherally confined in the mannersaforesaid;

d. moving said single, round, axially offset, hollow punchlongitudinally through said work-piece while it is heated andperipherally confined in the manners set forth hereinbefore, to therebyobtain an axially off-set cylindrical bore of such size and shape as toconstitute the line pipe passage of the connector Tee and thereafter e,making a transversely extending opening through the wall of that portionof said work-piece which possesses the greater cross-sectional area, tothereby form a re-inforced branch pipe opening which extends atright-angles to, and communicates with, the line pipe passage of theconnector Tee,

f. the axially offset, single, round, hollow-punch being so positionedwith respect to the longitudinal axis of the work-piece throughout itsmovement with respect thereto as to assure the provision around thesubsequently formed branch pipe passage of sufficient metal tocompensate by way of reinforcement for the weakening of the wall of thework-piece caused by the formation of said branch pipe passage andwithout reducing the thickness of v the opposite portion of the wall ofthe work-piece below the bursting pressure of the connector Tee.

2. The method of claim 1 wherein the solid metal work-piece of roundcross-section is obtained by forging the same from a solid work-piece ofrectangular cross-section.

1. The method of making a metallic connector Tee for connecting pressurepipes of approximately 8-inch Nominal Pipe Size and a wall-thickness ofat least 0.718 inch. which consists essentially of a. heating a solidmetal work-piece of round cross-section and appropriate size to forgingtemperature; b. peripherally confining the so-heated solid metalwork-piece throughout substantially its entire length; c. positioning asingle, round, hollow punch longitudinally of said work-piece but inaxially off-set relationship with respect thereto while said work-pieceis heated and peripherally confined in the manners aforesaid; d. movingsaid single, round, axially offset, hollow punch longitudinally throughsaid work-piece while it is heated and peripherally confined in themanners set forth hereinbefore, to thereby obtain an axially off-setcylindrical bore of such size and shape as to constitute the line pipepassage of the connector Tee and thereafter e. making a transverselyextending opening through the wall of that portion of said work-piecewhich possesses the greater cross-sectional area, to thereby form are-inforced branch pipe opening which extends at right-angles to, andcommunicates with, the line pipe passage of the connector Tee, f. theaxially offset, single, round, hollow-punch being so positioned withrespect to the longitudinal axis of the workpiece throughout itsmovement with respect thereto as to assure the provision around thesubsequently formed branch pipe passage of sufficient metal tocompensate by way of reinforcement for the weakening of the wall of thework-piece caused by the formation of said branch pipe passage andwithout reducing the thickness of the opposite portion of the wall ofthe work-piece below the bursting pressure of the connector Tee.
 2. Themethod of claim 1 wherein the solid metal work-piece of roundcross-section is obtained by forging the same from a solid work-piece ofrectangular cross-section.